Dec. 12, 2000 (Washington) -- A new type of magnetic resonance imaging technology may soon help doctors diagnose acute stroke, as well as assess certain neurological, cognitive, and behavioral disorders such as autism, attention deficit disorder, and schizophrenia.
MRI is an imaging technique used to produce high quality images of the inside of the human body. The new technique is called Diffusion Tensor Magnetic Resonance Imaging, or DT-MRI. It measures the random movement of hydrogen atoms within water (even "calm" water will have a lot of atomic movement within it) in a noninvasive fashion. These randomly moving atoms collide with each other and spread out in a process called diffusion.
By also tracking the diffusion, or spread, of water molecules during an MRI, the technique allows for the three-dimensional mapping of soft tissues such as nerves, muscles, and the heart.
"It's MRI plus," says Peter Basser, PhD, who developed the system in 1996. Now chief of tissue biophysics and biometrics at the National Institute of Child Health and Human Development (NICHD), Basser says the best thing about his technique is that it will allow for the mapping of nerve pathways in the brain.
Using his technique, researchers will be able to depict the fibers that connect different regions of the brain, and then map the spread of the water molecules in order to determine how the brain is "wired," Basser explains. This map can then be used to look for common "wiring" problems related to conditions such as autism, multiple sclerosis, and epilepsy, he tells WebMD.
Basser's technique is not yet in commercial development, although a number of companies have expressed interest. But research into its practical application already has begun. Some of that research was described at a recent conference hosted by NICHD.
At the meeting, researchers from across the globe described their efforts to diagnose conditions ranging from alcoholism to schizophrenia, as well as map tumors, the spinal cord, and heart. But in describing their successes, the researchers also depicted some of the remaining hurdles including one that many take some time to sort out.
At present, there is no real way to confirm that the anatomical data gathered by the researchers truly is valid, explains Carlo Pierpaloi, MD, PhD, a co-developer of the technique and the first researcher to investigate its practical applications. Without that anatomical confirmation, it will be difficult to put the technology into practice, the NICHD researcher adds.
At the heart of the problem is whether dead human tissue is comparable to live human tissue. Because the researchers are unable to dissect a live human brain, the present comparisons are between what is seen in dead dissected specimens and what is seen in living specimens imaged by the new technology.
Animal studies may help resolve part of this problem, Pierpaloi observes. But because certain human-like behavioral conditions are difficult, if not impossible at times, to identify in animals, solving this quandary is of significant importance, Pierpaloi tells WebMD.
There are also some technical problems to be worked out for different applications such as how to limit background distortions, Pierpalosi and the other researchers say. But nonetheless, "It is clearly an important technology for the future," Pierpalosi concludes.
Still, the technique may have some immediate applications. For instance, drug makers could use it as "in-house" technology to test the effectiveness of drugs under investigation, Basser tells WebMD.
Basser says he expects that the technique will be phased in over time. But besides specialized hardware, it also requires an understanding of diffusion principles. "It's a challenging thing to do right now," Basser says.
As for the human brain scans, the process may also be difficult for some to undergo. For the three-dimensional image to be generated, the process requires about 15 to 30 minutes of staying absolutely still -- on top of the hour or so it already takes to complete a traditional MRI.
Additional information about DT-MRI and some sample images can be seen at www.nichd.nih.gov.